海域超软土地层大直径盾构掘进控制研究

Research on Control of Large-diameter Shield Tunneling in Super-soft Soil Strata in Marine Areas

随着我国轨道交通事业的高速发展,穿江越海盾构工程逐年增加,地层稳定性分析及控制成为研究热点。本文以粤港澳大湾区横琴杧洲穿海盾构隧道工程为工程实例,通过PLAXIS 3D建立三维有限元模型,定量分析了盾构掘进过程加固范围、地表沉降等时变特征。结合现场实测数据,明确了海域超软土地层大直径盾构掘进过程中地层的变形规律,验证了数值模拟的可靠性。研究表明:盾构隧道开挖时,地表允许最大沉降为20mm,当t>0.15D,地表沉降满足要求,加固范围取0.20D最为合理,当t=0.00D时,地表最大沉降约50mm,当t=0.20D时,地表最大沉降约8mm,相比t=0.00D最大沉降减少约84%。结合研究结果所得规律,设计了盾构隧道软土地基加固方案,取得了理想效果。研究可为类似工程提供有价值的参考。

With the rapid development of China's railway transportation industry,the construction of shield tunneling projects across rivers and seas has increased year by year,making the analysis and control of stratum stability a research hotspot.Taking the Hengqin-Macao Undersea Shield Tunnel project in the Guangdong-Hong Kong-Macao Greater Bay Area as an engineering example,this paper establishes a three-dimensional finite element model using PLAXIS 3D to quantitatively analyze the time-varying characteristics of shield tunneling reinforcement range and surface settlement.Combined with field measurement data,the deformation law of the strata during the shield tunneling process in the extremely soft soil layer of the sea area is clarified,verifying the reliability of numerical simulation.The research indicates that during shield tunnel excavation,the maximum allowable surface settlement is 20 mm.When t>0.15D,the surface settlement meets the requirements,and a reinforcement range of 0.20D is the most reasonable.When t=0.00D,the maximum surface settlement is about 50 mm,and when t=0.20D,the maximum surface settlement is about 8 mm,representing a reduction of approximately 84%compared to t=0.00D.Combined with the law obtained from the research results,the reinforcement scheme of soft soil foundation of shield tunnel is designed,and the ideal effect is obtained.This study provides valuable references for similar engineering projects.